Torque sensor and steering apparatus including same

ABSTRACT

The present invention may provide a torque sensor including: a rotor; a stator disposed outside the rotor; a sensor assembly configured to measure a magnetic field generated between the rotor and the stator, and a housing; the rotor and the stator are disposed outside the housing, the sensor assembly is disposed inside the housing and includes an alignment means configured to align a position of the housing with a position of the stator in a direction of an axis of the rotor, and the alignment means is disposed on at least one of the housing and the stator.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the National Phase of PCT International ApplicationNo. PCT/KR2017/015532, filed on Dec. 27, 2017, which claims priorityunder 35 U.S.C. 119(a) to Patent Application Nos. 10-2016-0181102, filedin the Republic of Korea on Dec. 28, 2016; 10-2017-0012013, filed in theRepublic of Korea on Jan. 25, 2017 and 10-2017-0012771, filed in theRepublic of Korea on Jan. 26, 2017, all of which are hereby expresslyincorporated by reference into the present application.

TECHNICAL FIELD

The present invention relates to a torque sensor and a steeringapparatus including the same.

BACKGROUND ART

An electronic power system (EPS) drives a motor using an electroniccontrol unit (ECU) according to traveling conditions to ensure turningstability and rapidly provide a restoring force so that a driver cantravel stably.

In order to provide a proper torque, the EPS includes a torque sensorconfigured to measure torque of a steering shaft. The steering shaft mayinclude an input shaft connected to a handle, an output shaft connectedto a power transmission system of a side of a wheel, and a torsion barwhich connects the input shaft to the output shaft.

The torque sensor measures torque applied to the steering shaft bymeasuring the degree of torsion of the torsion bar. Such a torque sensormay include a rotor, a stator, and a sensor assembly. The sensorassembly may include a collector configured to measure an amount ofmagnetization of the stator.

Meanwhile, there is a compact torque sensor in which a sensor assemblyand a stator are individually formed. However, since the sensor assemblyand the stator of the torque sensor are individually formed, there areproblems in that an error in alignment position occurs between thestator and the collector, and torque may not be measured accurately.

In addition, the sensor assembly is included in a separate housing. Thehousing includes a collector configured to collect a magnetic field ofthe stator. Here, a substrate of the sensor assembly is fixed to thehousing. When a gap is formed between the substrate and the collector,since a signal becomes inaccurate, the substrate and the housing shouldbe fixed using a separate member.

However, a configuration, in which the housing and the substrate arefixed using a screw or the substrate and the housing are fixed bythermosetting, has a problem in that manufacturing processes andmanufacturing costs are increased.

In addition, the sensor assembly may be connected to an ECU. Here, ahigh current of the ECU may negatively affect performance of the sensorassembly. Accordingly, in order to avoid the high current of the ECU,the sensor assembly and the ECU of a vehicle are spaced apart from eachother and connected to each other through a wire harness. However, sucha configuration has a problem in that the size of a product isincreased.

DISCLOSURE Technical Problem

The present invention is directed to providing a torque sensor, in whicha sensor assembly and a stator are individually formed, capable ofsecuring an alignment position between the stator and a collector, and asteering apparatus including the same.

In addition, the present invention is directed to providing a torquesensor, in which a substrate is fixed to a slot without a separatecoupling member, and a steering apparatus including the same.

In addition, the present invention is directed to providing a torquesensor capable of reducing a size of a product while a high current ofan electronic control unit of a vehicle is avoided, and a steeringapparatus including the same.

Objectives to be solved by embodiments are not limited to theabove-described objectives and will include objectives and effects whichcan be identified by solutions for the objectives and the embodimentsdescribed below.

Technical Solution

One aspect of the present invention provides a torque sensor including arotor, a stator disposed outside the rotor, a sensor assembly configuredto measure a magnetic field generated between the rotor and the stator,and a housing, wherein the rotor and the stator are disposed outside thehousing, the sensor assembly is disposed inside the housing and includesan alignment means configured to align a position of the housing with aposition of the stator in a direction of an axis of the rotor, and thealignment means is disposed on at least one of the housing and thestator.

The alignment means may include a groove disposed in the stator and aprotrusion disposed on the housing and corresponding to a position ofthe groove.

The stator may include a mold member and a stator tooth fixed to themold member, and the groove may be disposed in the mold member.

The groove may be disposed in an annular shape along an outercircumferential surface of the mold member.

The housing may include a front surface which faces the stator, and theprotrusion may protrude from the front surface.

The housing may include the front surface which faces the stator, andthe front surface may include a curved surface portion.

A radius of a curvature of the curved surface portion may be at leastgreater than that of a stator tooth of the stator.

The protrusion may be disposed on the curved surface portion.

The front surface may include flat surface portions disposed at bothends of the curved surface portion.

The sensor assembly may include a collector configured to collect themagnetic field and a substrate including a sensor configured to measurethe magnetic field collected by the collector.

The housing may include a slot into which the substrate is inserted.

The housing may include a front surface which faces the stator and arear surface positioned opposite the front surface, and the slot maypass through from the rear surface to the front surface.

The substrate may include a connector, and the substrate may beaccommodated in the housing such that the connector is externallyexposed.

The housing may include a first coupling portion, and the collector mayinclude a second coupling portion coupled to the first coupling portion.

The first coupling portion may be a protruding pin, and the secondcoupling portion may be a hole through which the pin passes.

The collector may include an upper collector and a lower collector, andthe alignment means may be disposed between the up collector and thelower collector in the direction of an axis of the rotor.

The housing may include the slot into which the substrate is inserted,the collector may include the upper collector and the lower collector,and the slot may be disposed between the upper collector and the lowercollector in the direction of the axis of the rotor.

The housing may include a coupling portion into which a coupling memberis inserted.

Another aspect of the present invention provides a steering apparatusincluding a torque sensor, and an electronic control unit connected tothe torque sensor, wherein the torque sensor includes a rotor, a statordisposed outside the rotor, a sensor assembly configured to measure amagnetic field generated between the rotor and the stator, and ahousing, wherein the rotor and the stator are disposed outside thehousing, the sensor assembly is disposed inside the housing and includesan alignment means configured to align a position of the housing with aposition of the stator in a direction of an axis of the rotor, and thealignment means is disposed on at least one of the housing and thestator.

The housing may be coupled to a housing of the electronic control unit.

Still another aspect of the present invention provides a torque sensorincluding a rotor, a stator disposed outside the rotor, and a sensorassembly configured to measure a magnetic field generated between therotor and the stator, wherein the sensor assembly includes a housing,the rotor and the stator are disposed outside the housing, the housingincludes a front surface which faces the stator, a rear surfacepositioned opposite the front surface, and a slot which passes throughthe front surface from the rear surface and into which a substrate ofthe sensor assembly is inserted, wherein the slot includes first hookportions disposed on an inner wall of the slot, and the substrateincludes second hook portions disposed on both side surfaces of thesubstrate to be hooked on the first hook portions in a direction inwhich the substrate is inserted thereinto.

The first hook portion may include a stepped portion, and the secondhook portion may include a protrusion configured to be hooked on thestepped portion.

The substrate may include stoppers disposed at both side surfaces of thesubstrate and behind the second hook portions and configured to comeinto contact with an inlet of the slot.

The housing may include guides which are disposed at both sides of theinlet of the slot and into which the substrate is inserted.

The stopper may come into contact with an end of the guide.

The substrate may include a connector, and the connector may be disposedoutside the housing in a state in which the first hook portion and thesecond hook portion are hooked on each other.

The housing may include a collector configured to collect a magneticfield of the stator, the collector may include an upper collector and alower collector, and the slot may be disposed between the uppercollector and the lower collector in a direction of an axis of therotor.

The substrate may include a sensor configured to measure the magneticfield collected by the collector.

The housing may include a coupling portion into which a coupling memberis inserted.

Yet another aspect of the present invention provides a steeringapparatus including a torque sensor, and an electronic control unitconnected to the torque sensor, wherein the torque sensor includes arotor, a stator disposed outside the rotor, and a sensor assemblyconfigured to measure a magnetic field generated between the rotor andthe stator, wherein the sensor assembly includes a housing, the rotorand the stator are disposed outside the housing, the housing includes afront surface which faces the stator, a rear surface positioned oppositethe front surface, and a slot which passes through the front surfacefrom the rear surface and into which a substrate of the sensor assemblyis inserted, the slot includes first hook portions disposed on an innerwall of the slot, and the substrate includes second hook portionsdisposed on both side surfaces of the substrate to be hooked on thefirst hook portions in a direction in which the substrate is insertedthereinto.

The housing may be coupled to a housing of the electronic control unit.

Yet another aspect of the present invention provides a torque sensorincluding a rotor, a stator disposed outside the rotor, and a sensorassembly configured to measure a magnetic field generated between therotor and the stator, wherein the sensor assembly includes a housing,the rotor and the stator are disposed outside the housing, the housingincludes a collector and a back yoke, the rotor and the stator aredisposed in front of the collector, and the back yoke is disposed behindthe collector.

The housing may include a front surface which faces the stator, a rearsurface positioned opposite the front surface, and a slot which passesthrough the front surface from the rear surface and into which asubstrate of the sensor assembly is inserted.

The back yoke may be disposed on the rear surface of the housing.

The housing may include a back yoke accommodation portion which isconcavely disposed in the rear surface and accommodates the back yoke.

The back yoke may include a protrusion which protrudes from an edgethereof, and the back yoke accommodation portion may include a grooveportion at which the protrusion is positioned.

The back yoke may include a first hole which is disposed to be alignedwith the slot and through which the substrate passes.

Guides may be provided to be disposed at both sides of an inlet of theslot, and the substrate may be inserted therein.

The back yoke may include second holes through which the guides pass.

The substrate may include a connector, and the connector may be disposedoutside the housing in a state in which the first hook portion and thesecond hook portion are hooked on each other.

The collector may include an upper collector and a lower collector, andthe slot may be disposed between the upper collector and the lowercollector in a direction of an axis of the rotor.

The substrate may include a sensor configured to measure the magneticfield collected by the collector.

The housing may include a coupling portion into which the couplingmember is inserted.

Yet another aspect of the present invention provides a steeringapparatus including a torque sensor and an electronic control unitconnected to the torque sensor, wherein the torque sensor includes arotor, a stator disposed outside the rotor, and a sensor assemblyconfigured to measure a magnetic field generated between the rotor andthe stator, wherein the sensor assembly includes a housing, the rotorand the stator are disposed outside the housing, the housing includes acollector and a back yoke, the rotor and the stator are disposed infront of the collector, and the back yoke is disposed behind thecollector.

The housing may be coupled to a housing of the electronic control unit.

Advantageous Effects

According to an embodiment, since an alignment position is securedbetween a stator tooth and a collector using an alignment means which isconfigured to align a position of a housing with a position of a stator,an advantageous effect of improving torque performance is provided.

Since a substrate is configured to be installed by being inserted into aslot and the substrate is inserted into the slot without a separatecoupling member, advantageous effects of simplifying a manufacturingprocess and reducing a manufacturing cost are provided.

When the substrate is assembled in the housing, since the couplingmember is not used, an advantageous effect of removing a manufacturingdefect, which can occur in a coupling process, is provided.

Since a high current of an electronic control unit is blocked by a backyoke, a gap between the sensor assembly and the electronic control unitis decreased, and thus an advantageous effect of reducing an overallsize of a product is provided.

Since a wire harness configured to connect the sensor assembly and theelectronic control unit is removed, an advantageous effect of reducing amanufacturing cost is provided.

DESCRIPTION OF DRAWINGS

FIG. 1 is a view illustrating a torque sensor according to anembodiment.

FIG. 2 is an exploded view illustrating the torque sensor illustrated inFIG. 1.

FIG. 3 is a view illustrating a housing.

FIG. 4 is a view illustrating a curved surface portion disposed on afront surface of the housing.

FIG. 5 is a view illustrating the housing including a protrusion of analignment means.

FIG. 6 is a view illustrating a stator including a groove of thealignment means.

FIG. 7 is a view illustrating a position at which the stator is alignedwith a collector.

FIG. 8 is a view illustrating a state in which a protrusion of thehousing is coupled to a groove of the stator.

FIG. 9 is a front view illustrating the housing seen from the front.

FIG. 10 is a view illustrating a substrate.

FIG. 11 is a view illustrating an interior of a slot of the housing.

FIG. 12 is a plan view illustrating the housing into which the substrateis inserted.

FIG. 13 is a view illustrating a torque sensor being coupled to anelectronic control unit.

FIG. 14 is a view illustrating the housing and a back yoke.

FIG. 15 is a plan view illustrating the back yoke illustrated in FIG.14.

FIG. 16 is an enlarged view illustrating a region A of FIG. 14.

FIG. 17 is a side cross-sectional view illustrating the torque sensorillustrated in FIG. 1.

FIG. 18 is a comparative view of a magnetic flux density of thecollector of a sensor assembly in which the back yoke is disposed and amagnetic flux density of the collector of the sensor assembly in whichthe back yoke is not disposed.

MODES OF THE INVENTION

Hereinafter, exemplary embodiments of the present invention will bedescribed in detail with reference to the accompanying drawings.Purposes, specific advantages, and novel features of the invention willbe made clear from the exemplary embodiments and the following detaileddescription in connection with the accompanying drawings. In thedescription of the invention, when it is determined that detaileddescriptions of related well-known functions unnecessarily obscure thegist of the invention, the detailed descriptions thereof will beomitted.

It will be understood that, although the terms “first,” “second,” etc.may be used herein to describe various elements, these elements shouldnot be limited by these terms. These terms are only used to distinguishone element from another. For example, a first element could be termed asecond element, and a second element could similarly be termed a firstelement without departing from the scope of the present invention. Asused herein, the term “and/or” includes combinations or any one of aplurality of associated listed items.

FIG. 1 is a view illustrating a torque sensor according to anembodiment, and FIG. 2 is an exploded view illustrating the torquesensor illustrated in FIG. 1.

Referring to FIGS. 1 and 2, a torque sensor 10 may include a rotor 100,a stator 200, a sensor assembly 300, and a housing 400.

The rotor 100 is disposed inside the stator 200. The rotor 100 isconnected to an input shaft of a steering shaft. Here, the input shaftmay be a steering shaft connected to a handle of a vehicle. The rotor100 may include a yoke 110 having a cylindrical shape and a magnet 120disposed around the yoke 110. The input shaft is inserted into the yoke110. In addition, the magnet 120 may be disposed outside the yoke 110.The magnet 120 may be fixed to an outer circumferential surface of theyoke 110 by being adhered or press-fitted thereto.

The stator 200 is disposed outside the rotor 100. The stator 200 mayinclude stator teeth 210 having an annular shape, a mold member 220, anda holder 230. The pair of stator teeth 210 facing each other, may bedisposed to be spaced apart from each other. In addition, two statorteeth 210 may be fixed to an upper side and a lower side of the moldmember 220. The holder 230 is coupled to the mold member 220. The holder230 may be connected to an output shaft of the steering shaft. Here, theoutput shaft may be a steering shaft connected to a power transmissionsystem of a side of a wheel. Accordingly, the stator 200 is connected tothe output shaft to rotate with the output shaft.

The sensor assembly 300 measures a magnetic field generated between therotor 100 and the stator 200. The sensor assembly 300 is connected to anelectronic control unit (ECU) of a motor, which assists steering,calculates torque on the basis of a measured magnetic field, andtransmits the torque to the ECU.

The sensor assembly 300 may include a collector 310 and a substrate 320including a sensor 321.

The collector 310 collects a flux of the stator 200. The collector 310may include an upper collector 311 and a lower collector 312. The uppercollector 311 and the lower collector 312 may be disposed to be spacedapart from each other in a direction of an axis of the rotor 100.

The substrate 320 includes the sensor 321. The sensor 321 may be a Hallintegrated circuit (IC) which detects a change in a magnetic field. Thesensor 321 detects an amount of magnetization of the stator 200generated due to an electrical interaction between the magnet 120 of therotor 100 and the stator 200. The sensor 321 is disposed between theupper collector 311 and the lower collector 312 in the direction of theaxis of the rotor 100. The substrate 320 includes a connector 322. Theconnector 322 is connected to an ECU.

FIG. 3 is a view illustrating a housing.

Referring to FIGS. 2 and 3, the housing 400 fixes the collector 310 andthe substrate 320. In addition, the housing 400 is disposed outside therotor 100 and the stator 200. The housing 400 may be disposed in ahousing (not shown) of the ECU. The housing 400 may include a slot 410into which the substrate 320 is inserted. The slot 410 is disposed topass through a front surface 400A and a rear surface 400B of the housing400.

The front surface 400A of the housing 400 may denote a surface whichfaces the stator 200 when the housing 400 is disposed in the housing theECU, the rear surface 400B of the housing 400 is positioned in adirection opposite the front surface 400A, and an inlet of the slot 410into which the substrate 320 is inserted is positioned in the rearsurface 400B. Guides 411 may be disposed at both sides of the inlet ofthe slot 410. Both edges of the substrate 320 are inserted into theguides 411. The substrate 320 is inserted into the slot 410 along theguides 411. In a state in which the substrate 320 is inserted into theslot 410, the connector 322 is positioned outside the housing 400. Aplurality of coupling portions 412 which are coupled to the housing ofthe ECU may be provided in the housing 400.

FIG. 4 is a view illustrating a curved surface portion disposed on afront surface of the housing.

Referring to FIGS. 3 and 4, the front surface 400A of the housing 400may include a curved surface portion 420 and flat surface portions 430.A radius R1 of a curvature of the curved surface portion 420 may be atleast greater than a radius R2 of a curvature of the stator teeth 210.The flat surface portions 430 are disposed at both sides of the curvedsurface portion 420. A plurality of coupling protrusions 440 may bedisposed on the flat surface portions 430. The coupling protrusions 440are coupled to the collector 310.

FIG. 5 is a view illustrating the housing including a protrusion of analignment means, FIG. 6 is a view illustrating a stator including agroove of the alignment means, and FIG. 7 is a view illustrating aposition at which the stator is aligned with a collector.

Referring to FIGS. 5 to 7, an alignment means serves to align a positionof the stator teeth 210 with a position of the collector 310 in thedirection of the axis of the rotor 100. Since the stator 200 includingthe stator teeth 210 is connected to the steering shaft and the housing400 including the collector 310 is connected to the housing of the ECU,there is a high risk in that an error in alignment occurs between theposition of the stator teeth 210 and the position of the collector 310.The alignment means physically connects the stator 200 and the housing400 to reduce the error in alignment.

The alignment means includes a protrusion 450 disposed on the housing400 and a groove 221 provided in the mold member 220 of the stator 200.

The protrusion 450 is disposed on the front surface 400A of the housing400. Specifically, the protrusion 450 may be disposed on the curvedsurface portion 420 of the housing 400. The protrusion 450 may bedisposed between the upper collector 311 and the lower collector 312 inthe direction of the axis of the rotor 100. In addition, a front surface451 of the protrusion 450 may be formed to have a curved surface.

The groove 221 is disposed along an outer circumferential surface of themold member 220. The groove 221 is concavely formed in the outercircumferential surface of the mold member 220. In addition, an overallshape of the groove 221 may be an annular shape.

When the groove 221 is aligned with the protrusion 450 in the directionof the axis of the rotor 100, the stator teeth 210 are aligned with thecollector 310.

FIG. 8 is a view illustrating a state in which to protrusion of thehousing is coupled to a groove of the stator.

Referring to FIG. 8, when the groove 221 and the protrusion 450 arecoupled, the stator teeth 210 are aligned with the collector 310 in thedirection of the axis of the rotor 100. Accordingly, in the torquesensor in which the stator 200 and the sensor assembly 300 areindividually disposed, the torque sensor according to the embodiment canhave an advantage of improving torque performance.

FIG. 9 is a front view illustrating the housing seen from the front.

Referring to FIG. 9, the slot 410 may be disposed between the uppercollector 311 and the lower collector 312 in the direction of the axisof the rotor 100. Accordingly, the substrate 320 inserted into the slot410 may also be disposed between the upper collector 311 and the lowercollector 312.

FIG. 10 is a view illustrating a substrate.

Referring to FIG. 10, the substrate 320 may include second hook portions323. The second hook portions 323 serve to fix the substrate 320 to theslot 410 so that the substrate 320 is not withdrawn from the slot 410 ina state in which the substrate 320 is inserted into the slot 410.

The second hook portions 323 may be disposed at both side surfaces ofthe substrate 320. The second hook portions 323 may be protrusions whichprotrude from the both side surfaces of the substrate 320. The secondhook portions 323 may be disposed in a front of the substrate 320. Thesensor 321 is disposed in the front of the substrate 320. A protrusionof the second hook portion 323 may include an inclined surface which isinclined in a rear direction, and an end portion thereof may be formedto have a stepped portion. When the substrate 320 is inserted into theslot 410, the second hook portions 323 are hooked on first hook portions413 while moving along an inner wall of the slot 410.

The substrate 320 may include stoppers 324. When the substrate 320 isinserted into the slot 410, the stopper 324 serves to prevent thesubstrate 320 from being inserted into the slot 410 beyond an originalposition.

The stopper 324 may be disposed in a rear of the substrate 320. Theconnector 322 is disposed in the rear of the substrate 320. The stoppers324 are disposed on the both side surfaces of the substrate 320 to havestepped portions. When the substrate 320 is inserted into the slot 410,the stoppers 324 come into contact with ends of guides 411 to preventthe substrate 320 from being inserted into the slot 410 more thannecessary.

FIG. 11 is a view illustrating an interior of a slot of the housing.

Referring to FIG. 11, the first hook portion 413 is disposed on theinner wall of the slot 410. The first hook portion 413 includes astepped portion.

When the substrate 320 is inserted into the slot 410, the second hookportions 323 are hooked on the first hook portions 413 having a steppedshape. Accordingly, when the substrate 320 is about to be withdrawn fromthe slot 410, the second hook portions 323 of the substrate 320 arehooked on the first hook portions 413 of the slot 410 so that thesubstrate 320 is not withdrawn from the slot 410.

In addition, when the substrate 320 is inserted into the slot 410 andthe sensor 321 is aligned with a target position, the stoppers 324 ofthe substrate 320 are hooked on the ends of the guides 411 so that thesubstrate 320 is prevented from being excessively inserted into the slot410.

FIG. 12 is a plan view illustrating the housing into which the substrateis inserted.

Referring to FIGS. 11 and 12, in a state in which the substrate 320 isinserted into the slot 410, the connector 322 is positioned outside thehousing 400. When the substrate 320 is inserted into the slot 410, aspace in which the connector 322 is disposed is secured due to theguides 411 which protrude from the inlet of the slot 410. The connector322 may be coupled to a connector of an ECU of the vehicle. Accordingly,in a state in which the substrate 320 is inserted into the slot 410, thesubstrate 320 is primarily fixed by the first hook portions 413 and thesecond hook portions 323 and secondarily fixed by the connector 322being coupled to the connector of the ECU of the vehicle so that thesubstrate 320 can be stably fixed without a separate coupling member.

FIG. 13 is a view illustrating a torque sensor being coupled to an ECU.

Referring to FIG. 13, the torque sensor 10 may be connected adjacent toan ECU 20. Here, a high current generated by the ECU 20 may affect thetorque sensor 10.

FIG. 14 is a view illustrating the housing and a back yoke.

Referring to FIG. 2 and FIG. 14, the housing 400 may include the backyoke. The back yoke 460 serves to block a high current of the ECU 20from being induced into the sensor assembly 300. When the stator 200 isdisposed in front of the collector 310, the back yoke 460 may bedisposed behind the collector 310. This is to prevent the high currentof the ECU 20 from affecting the collector 310.

For example, the back yoke 460 may be disposed on the rear surface 400Bof the housing 400. A back yoke accommodation portion 470 may beprovided in the rear surface 400B of the housing 400. The back yokeaccommodation portion 470 may be concavely disposed in the rear surface400B of the housing 400. The back yoke 460 is seated on the back yokeaccommodation portion 470. The back yoke 460 may have a quadrilateralplate shape, but the present invention is not limited thereto and may bevariously modified by considering a shape of the rear surface 400B ofthe housing 400.

The back yoke 460 may include a first hole 461 through which thesubstrate 320 passes. The first hole 461 has an elongated shape which islaterally disposed. When the back yoke 460 is installed in the back yokeaccommodation portion 470, the first hole 461 is aligned with the slot410. In addition, the back yoke 460 may include second holes 462 throughwhich the guides 411 pass. The second hole 462 has an elongated shapewhich is vertically disposed by considering the shape of the guide 411.The first hole 461 may be connected to the second holes 462.

FIG. 15 is a plan view illustrating the back yoke illustrated in FIG.14.

Referring to FIGS. 14 and 15, the back yoke 460 may include a main plate460A including the first hole 461 and the second holes 462 and sideplates 460B disposed to be bent from both sides of the main plate 460A.The side plates 460B may include protrusions 463.

FIG. 16 is an enlarged view illustrating a region A of FIG. 14.

Referring to FIGS. 14 and 16, groove portions 471 may be provided inboth side walls of the back yoke accommodation portion 470. Theprotrusion 463 of the back yoke 460 is inserted into the groove portion471. The groove portions 471 and the protrusions 463 prevent the backyoke 460 from being withdrawn from the back yoke accommodation portion470.

FIG. 17 is a side cross-sectional view illustrating the torque sensorillustrated in FIG. 1.

As illustrated in FIG. 17B, the upper collector 311 and the lowercollector 312 are disposed with the sensor 321 therebetween. When a highcurrent is introduced into the ECU 20 (see FIG. 3), a change in magneticflux occurs at a portion of the collector 310 which faces the sensor321. When the change in magnetic flux occurs due to disturbance at theportion of the collector 310, a critical problem occurs that torque maynot be measured accurately. The back yoke 460 disposed behind thecollector 310 blocks a high current introduced from the ECU 20 (see FIG.3) so as to prevent the change in magnetic flux occurring due todisturbance at the portion of the collector 310.

FIG. 18 is a comparative view of a magnetic flux density of thecollector of a sensor assembly in which the back yoke is disposed and amagnetic flux density of the collector of the sensor assembly in whichthe back yoke is not included.

FIG. 18A shows a magnetic flux density of the collector 310 of thesensor assembly 300 in which the back yoke is not disposed, and themeasured magnetic flux density thereof is 0.2987 mT. FIG. 18B shows amagnetic flux density of the collector of the sensor assembly in a statein which the back yoke 460 is disposed, and the measured magnetic fluxdensity is 0.2078 mT.

It may be seen that the magnetic flux density of the collector 310 ofthe sensor assembly 300 which does not include the back yoke isrelatively high. This is because the magnetic flux density is affectedby a high current introduced from the ECU 20 (see FIG. 13). However, ina state in which the back yoke 460 is disposed therein, since the backyoke 460 blocks a high current introduced due to disturbance, it may beseen that a normal magnetic flux density is measured.

As described above, the torque sensor and the steering apparatusincluding the same according to one exemplary embodiment of the presentinvention have been specifically described with reference to theaccompanying drawings.

The above-described embodiments of the present invention should beunderstood in a descriptive sense only and not for purposes oflimitation. The scope of the present invention is defined not by theabove-described detailed description but by the appended claims whichwill be described below. In addition, it should be interpreted that thescope of the present invention encompasses all modifications andalterations derived from meanings, the scope, and equivalents of theappended claims.

The invention claimed is:
 1. A torque sensor comprising: a rotor; astator disposed outside the rotor; a sensor assembly configured tomeasure a magnetic field generated between the rotor and the stator; anda housing; the rotor and the stator are disposed outside the housing,the sensor assembly is disposed inside the housing and includes analignment means configured to align a position of the housing with aposition of the stator in a direction of an axis of the rotor, and thealignment means is disposed on at least one of the housing and thestator, wherein the alignment means includes a groove disposed in thestator and a protrusion disposed in the housing and corresponding to aposition of the groove, and wherein the housing includes a front surfacewhich faces the stator and the front surface includes a curved surfaceportion, and the protrusion protrudes from the curved surface.
 2. Thetorque sensor of claim 1, wherein the collector includes an uppercollector and a lower collector, and the protrusion is disposed betweenthe upper collector and the lower collector in the direction of an axisof the rotor.
 3. The torque sensor of claim 2, wherein: the statorincludes a mold member and a stator tooth fixed to the mold member; andthe groove is disposed in the mold member.
 4. A steering apparatuscomprising: a torque sensor; and an electronic control unit connected tothe torque sensor, wherein the torque sensor includes a rotor, a statordisposed outside the rotor, a sensor assembly configured to measure amagnetic field generated between the rotor and the stator, and ahousing, wherein the rotor and the stator are disposed outside thehousing, the sensor assembly is disposed inside the housing and includesan alignment means configured to align a position of the housing with aposition of the stator in a direction of an axis of the rotor, and thealignment means is disposed on at least one of the housing and thestator, wherein the alignment means includes a groove disposed in thestator and a protrusion disposed in the housing and corresponding to aposition of the groove, and wherein the housing includes a front surfacewhich faces the stator and the front surface includes a curved surfaceportion, and the protrusion protrudes from the curved surface.
 5. Atorque sensor comprising: a rotor; a stator disposed outside the rotor;and a sensor assembly configured to measure a magnetic field generatedbetween the rotor and the stator, wherein the sensor assembly includes ahousing, the rotor and the stator are disposed outside the housing, thehousing includes a front surface which faces the stator, a rear surfacepositioned opposite the front surface, and a slot which passes throughthe front surface from the rear surface and into which a substrate ofthe sensor assembly is inserted, wherein the slot includes first hookportions disposed on an inner wall of the slot, and the substrateincludes second hook portions disposed on both side surfaces of thesubstrate to be hooked on the first hook portions in a direction inwhich the substrate is inserted thereinto, and wherein the substrateincludes a stopper disposed at the rear of the second latching portionand contacting an inlet of the slot.
 6. The torque sensor of claim 5,wherein: the first hook portion includes a stepped portion; and thesecond hook portion includes a protrusion configured to be hooked on thestepped portion.
 7. A steering apparatus comprising: a torque sensor;and an electronic control unit connected to the torque sensor, whereinthe torque sensor includes a rotor, a stator disposed outside the rotor,and a sensor assembly configured to measure a magnetic field generatedbetween the rotor and the stator, wherein the sensor assembly includes ahousing, the rotor and the stator are disposed outside the housing, thehousing includes a front surface which faces the stator, a rear surfacepositioned opposite the front surface, and a slot which passes throughthe front surface from the rear surface and into which a substrate ofthe sensor assembly is inserted, the slot includes first hook portionsdisposed on an inner wall of the slot, and the substrate includes secondhook portions disposed on both side surfaces of the substrate to behooked on the first hook portions in a direction in which the substrateis inserted thereinto, and wherein the substrate includes a stopperdisposed at the rear of the second latching portion and contacting aninlet of the slot.
 8. A torque sensor comprising: a rotor; a statordisposed outside the rotor; and a sensor assembly configured to measurea magnetic field generated between the rotor and the stator, wherein thesensor assembly includes a housing, the rotor and the stator aredisposed outside the housing, the housing includes a collector and aback yoke, the rotor and the stator are disposed in front of thecollector, and the back yoke is disposed behind the collector, whereinthe housing includes: a front surface which faces the stator; a rearsurface positioned opposite the front surface; a slot which passesthrough the front surface from the rear surface and into which asubstrate of the sensor assembly is inserted; and guides which aredisposed at both sides of the inlet of the slot and into which thesubstrate is inserted, which the back yoke includes a first hole whichis disposed to be aligned with the slot and through which the substratepasses, and a second hole through which the guides pass.
 9. The torquesensor of claim 8, wherein the housing includes a back yokeaccommodation portion which is concavely disposed in the rear surfaceand accommodates the back yoke.
 10. A steering apparatus comprising: atorque sensor; and an electronic control unit connected to the torquesensor, wherein the torque sensor includes a rotor, a stator disposedoutside the rotor, and a sensor assembly configured to measure amagnetic field generated between the rotor and the stator, wherein thesensor assembly includes a housing, the rotor and the stator aredisposed outside the housing, the housing includes a collector and aback yoke, the rotor and the stator are disposed in front of thecollector, and the back yoke is disposed behind the collector, whereinthe housing includes: a front surface which faces the stator; a rearsurface positioned opposite the front surface; a slot which passesthrough the front surface from the rear surface and into which asubstrate of the sensor assembly is inserted; and guides which aredisposed at both sides of the inlet of the slot and into which thesubstrate is inserted, which the back yoke include a first hole which isdisposed to be aligned with the slot and through which the substratepasses, and a second hole through which the guides pass.